Staple driving machine



Jan. 3, 1950 R. E. PETERSON 2,493,640-

STAPLE DRIVING MACHINE Filed March 21, 1947 Patented Jan. 3, 1950 PATENTOFFICE STAPLE DRIVING MACHINE Roy E. Peterson, Norwalk, Conn., assignor,by mesne assignments, to The E. H. Hotchkiss Company, Norwalk, Conn., a.corporation of Delaware Application March 21, 1947, Serial No. 736,195

11 Claims.

sion the spring, with an automatic release to ,5

release the driver for operation by the spring to drive the staple. Thistype of machine is sometimes called a tacker. In this type of machine asnow generally constructed, the driver is connected to a reciprocalplunger having considl0 erable weight, which operates with the driverand through its momentum to impart a sort of hammer blow to the staple.This weight, however, slows up the action and speed of the driver,

and then after it has been gotten up to speed, 16

some means must be provided to arrest the movement of this relativelyheavy plunger. These are objectionable features, and due to the reducedspeed of the driver in the driving operation of the staple, there is atendency for the staple to D.

buckle and not penetrate the work properly.

It is an object of the vpresent invention to eliminate this weight orplunger on the staple driver and operate the driver directly from the Ihave devised the construction illustrated in the accompanying drawingforming a part of this specification. It is, however, to be understoodthe invention is not limited to the specific details of construction andarrangement shown, but may embody various changes and modificationswithin the scope of the invention.

In this drawing:

Fig. 1 is a. vertical longitudinal section through the device;

Fig. 2 is a horizontal section substantially on line 2-2 of Fig. 1;

Fig. 3 is a front view with the front plate removed, the plane of thefigure being substantially on line 3-3 of Fig. 1;

` Fig. 4 is a detail vertical section substantially on line 4-4 of Fig.1;

Fig. 5 is a detail section substantially on line 5--5 of Fig. 1;

Fig. 6 is a section of the upper portion of the device showing theoperating lever and the releasable pawl at about the time it releasesthe staple driver;

Figs. '7 and 8 are inner and top views respecspring, so that it isoperated at a much greater g5 tively of the guide plate at the front ofthe speed than is possible with the weighted driver, and there is lessdiiiiculty in arresting movement of the driver at the completion of thedriving operation. It has been found that 'the staples are driven betterwith a higher speed, :30

well as increased speed. In short, with this de- 240 vice much greaterspeed of the staple driver is effected than where weight or momentumrelied on, and as suggested, it has been found that increased speedgives better and more reliable setting of the staple.

It is also an object to provide an improved means for retracting thedriver by action of the operating lever in placing the driver andtensioning the spring for the driving operation.` v

A greater speed also reduces buck- 85 feed guide, and

Fig. 9 is a side elevation of the front end portion of the housing withthe front plate removed but shown in dotted lines.

The machine as illustrated comprises a housing I II including a pair ofside plates II, preferably stamped to form of sheet metal and enclosingan inner housing I2 of generally U-shaped cross section, comprising sidemembers I3 at the inner side of the side members II, and a front guidewall I4 connecting these side members I3. This front guide wall hasvertical slots I5 and I6 for certain of the operating members, as willbe later described. The side plates I I have their upper edges turnedinwardly to form the top of a hand grip as indicated at I'I, and has anelongated slot I8, the edges of which are similarly turned in as shownat I9, forming iianges which provide the lower part of the hand grip. Y

Mounted in the lower part of the housing between the side members l I isa staple guide bar 20 extending longitudinally of the machine. This ispreferably substantially U-shaped in cross section, as shown in Fig. 4,for lightness and also to With the foregoing and other objects in vieW.-50 permit its being formed of a strip of sheet metal.

bar 2U. Thus, should astaple become jammed in the lower end of theracewayor guide for the staple driver, plate or block 6U may be readilyremoved to permit removal of the jammed staple.

Means is provided for feeding the staples along the bar 20 to bring themsuccessively tothe driving position in the guide or raceway 30 under thestaple driver 3|. This comprises a substantially U-shaped follower 10resting on the top of the bar 20 and engaging the rear end of the staplestrip 1| to feed it forwardly along the bar. It is fed forwardly bymeans of a coil spring 12 embracing a guide rod 13 slidably secured atits forward end to the follower 10 by any suitable means, such as theloop 14 secured to the top wall of the follower. The inner end of therod is enlarged or headed at 13a to prevent the follower being slid offthe rod by the spring. The other end of this rod is connected at 15 tothe end wall 16 of a block 11 of inverted U-shape in cross section,preferably formed from sheet metal, and carrying on the underside of itstop wall a spring catch 18 carrying an upwardly projecting lug 19adapted to seat in an opening 80 in the top wall of the insert member39, the forward end 8| of the spring being curved downwardly so as tohave a camming action on the end of the top wall of member 39 to forceit downwardly when the block 11 is inserted in the end of the member 25.The push button 82 carried by this spring 18 projects through an openingin the top of the member 11 for depression of the spring 18 to releasethe catch 19. Adjacent this forward end the follower 1|) may have adownwardly extending lug 83 lanced and bent downwardly from its top wallto engage vthe front cross wall 84 at the end of the staple guide 20 tolimit forward movement of the follower when the last staple has beendriven and prevent the end of the follower moving into a position underthe staple driver 3 I In operation the parts are normally substantiallyin the position of Fig 1. Depression of the lever 35 downwardly or tothe right, as indicated by the arrow 85, will through the action of thepawl 34 raise the staple driver 3| to substantially the position of Fig.6, carrying with it the spring rod 32 to substantially the dotted lineposition of Fig. 1. This will tension the spring 32 and will raise thelower end portion of the driver 3| from its position in front of thestaple guide bar 20, permitting the forward staple 1|a to move into thelower end portion of the guide and raceway 3U under the lower end of thedriver 3| and into the driving position. As the lever 35 approaches itslower position carrying the pawl 34 to its upper position, as shown inFig, 6, the stationary member 5l! engages the cam surface 49 and shiftsthe pawl to the right, withdrawing its end 33 from the opening 31 in thestaple driver 3| and from the shoulder at the top of this opening. Thisreleases the driver 3|, permitting the spring rod 32 to operate itdownwardly to drive the staple. Downward movement of the driver 3| androd 32 will be arrested by the resilient bumper and stop 4|. Release ofthe handle 35 will permit it to be swung backwardly to the normalposition of Fig. l by action of the spring 53. This will carry pawl 34downwardly until its forward end 33 again snaps into the opening 31 inthe driver preparatory to the next operation.

It is to be especially noted that the spring 3'2 is connected directlyto the staple driver 3|, and that this driver comprises only theelongated nat steel strip, and that there is no weight or plunger or anyother element connected to this driver to add weight to it and addmomentum for a hammer blow, as is common with present types of machinesof this character. Therefore, the Vweight of the driver and its inertiaor momentum is reduced to a minimum as there is very little weight tothe flat strip 3|, Therefore, this driver is operated with much greaterspeed than is possible with the old type of driver, which includes aweighted plunger or similar carrying device for the driver, the inertiaof such a device greatly slowing up the speed of operation of thedriver, and the momentum or weight of the plunger or carrier for thedriver is relied on to give a hammer blow to the staple to drive it atthe end of the driving operation. With such a device a heavy spring isrequired and the speed of driving the staple is very much slower than inthe present device, and the weight or momentum of the carrier or plungerfor the driver is relied on to a large extent to drive the staple andsecure the necessary penetration of the prongs of the staple. In thepresent construction, because of the minimum weight and momentum of thedriver 3|, there is no blow or momentum of the weighted element reliedon, but a greatly increased speed of operation of the driver and drivingaction of the staple is secured over the old devices, this speed ofoperation securing better penetration of the prongs of the staple and,due to this much greater speed of the driving action and therefore themuch greater speed of the penetration of the prong, there is much lessdanger of the prongs folding or buckling during the driving operation,as they do not have time to buckle as they do in the old type of device.It has been found that speed is more important than weight or'momentumin properly and effectively driving the staples. This arrangement alsosimplifies the construction Iand tends to 'lightness or less weight.Also, as a lighter operating spring may be used, it is much more easilyoperated and less pressure is required in depressing the operating leverpreparatory to the staple driving operation. Operation of this deviceis, therefore, much less tiring on the operator, and it may be usedcontinuously much longer without fatigue.

'I'he driver retracting and release construction comprising theA bodilyslidable pawl 34 is also a material improvement over the old type ofconstruction involving merely a pivoted pawl depending on a runout ofthis pivoted pawl for the release. In this case a more substantialsupport is provided by the pawl, and as there is a positive shifting ofthe pawl for the release by means of the stop 50 and the cam 49, andtherefore a positive release at a certain time, the release can be moreaccurately and reliably controlled, insuring that the driver is notreleased until it is retracted to the proper position.

In loadingmore staples into the machine, it is merely necessary torelease the catch 19 by depressing. the button 82 and withdrawing theblock 11 and the follower 10. After the new staple strip is inserted onthe guide bar 20 the follower is also inserted from the rear end ontothis bar and the block 11 moved inwardly until caught by the catch 19,thus compressing the feed spring 12 and tensioning it so it may feed thestaples forwardly.

Should for any reason a staple become jammed under the driver 3| in thelower part of theraceway 30, the spring strip 65 may be swung laterallyto releaserrthe plate orblock 60, which may then be. removed to permitthe jammed staple to drop out.v Y .i i.

i ".Havin'g. thusv set forth the nature'of myinvention, what I'claimis:`

I. A staple driving; lmachine comprising a guide bar for a strip ofstaples, a substantially -flat staple driver mounted nfoi'..reciprocating .movement across the front end of the guide 'bar to drive.the individual staples in succession, a Vspring comprising arodfastened at one end and ai; the other directly engaging the driver forfoperating -it to drive the staples, a Ypivoted operating lever, and areleasable'pawl carried Ybythe lever normally engaging the driver toretractit totenrsiontlie spring and thenfrelease'the driver yfor thedriving operation.

2. A staple driving vmachine comprising a. guide bar for a staple strip,a staple driver mounted for `movement across the end of the'bar to drivea staple, means for. feeding the staples along the bar to drivingposition, a spring rod fastened at one end and ateits other end engaginga shoulder Y.on the driver to operate it, a pivoted operating a staplecomprising a substantially flat' elongated strip, Vmeans for feedingstaples along'the bar to driving position, a spring rod .fastenedk atone end and at its other jend engaging a shoulder on the driver tooperate` it, a pivoted operating lever, a releasable paivl on the leverengaging a shoulder on the driver to retract the driver to tension thespring and then release the driver for` the staple driving operation,and a resilient bumper under the spring to limit forward movement of thespring; n

4. A staple driving machine comprising a guide bar for a strip ofstaples, a driver' consisting of a light Weight substantially atelongated strip Vmounted for movement across the end ofthe bar to drivea staple, means for feeding staples along the bar to driving position, aspring comprising a rod fastened at one end and at: the other directlyengaging the driver strip to operate it, an operating lever, andVa'releasable pawl on the lever engaging the driver strip to retract it'to'tension the spring and then release the driver strip for the drivingoperation. 5. il ple driving machine comprising a guide bar for astrip-of staples, a driver' consisting of alight weight substantiallyflat elongated strip of substantially the samethickness-throughout.mounted for movement across the end'of the'bar todrive a staple, saidstrip being provided with verticallyrspaced shoulders, aY spring'comprising a rod fastened at 'one end and engagingonefof y.saidshoulders at the other lend tooperate'the driver ton drive a staple, anoperating lever, Yand a releasable patvlonthe lever engaging the otherYshoulder to retractthedriver and tension the spring and then .releasethe driver for the driving Y:operation: Y i. 1

6.' A staple driving machine comprising La guide bar for astrip ofstaples,'a driver consisting of a substantially flat Aelongated stripmounted for movement across the end of the' bar Ato drive a staple, saidstrip being provided vvitlrspaced Y Vto operate the drivenan operatinglever, and a rei8 leasable pawl on the lever engagingthe Iother shoulderto retract the driver to tension' the spring and then release saiddriver for the driving operation;

7. A staple drivingV machine comprising a guide bar for a strip ofstaples, a driver consistingy of a substantially flat elongated stripmounted for movement across'the end of the bar to drive a staple, saidstrip being provided with spaced shoulders, a spring rod fastened at oneend and at the other end engaging one of said shoulders to operate thedriverymeans engaging the other shoulder to retract the driver totension the spring and then release said driver for the drivingoperation, and a resilient bumper under the spring rod to limit thedriving movement.

8. A staple driving machine comprising a guide bar for a staple strip, astaple driver mounted for movement across the end of the bar to-d'rive astaple, means for feeding the staples along the bar to driving position,a spring engaging the driver for operating it, an operatinglever, a'pawlonrthe lever engaging a shoulder on the driver to retract it to tensionthe spring, cooperating guide means on the pawl and lever'mounting thepaivl for bodily slidingmovement on4 the lever Vforwardly toward andrearwardly from the shoulder, a spring tending to shift the pawl` towardthe shoulder, and cooperating cam means to shift the pawl bacliwardlyfrom said shoulder to release the `driver as it approaches its retractedposition.

9. A staple driving machine comprising a guide bar for a staple strip, astaple driver Ymounted for movement across the end oi the bar to Ydrivea staple, means for feeding the staples along the bar to drivingposition, a spring `engaging the driver for operating it, a shoulder'onthe driver, on operating lever, a releasable pavvl engaging saidshoulder andY mounted Von ther lever' for bodily sliding movement towardand from the shoulder, said Vpawl being adapted to retract the driver totension the spring by operation of the lever, a spring tending to holdthe pawl in engagement with the shoulder, a camsurface on' the pavvl,and a stationary member positioned to engage the cam ,tov shift thepavvl from the shoulder to release the driveras itv approaches theretracted position.

10. A staple driving machineY comprising a guide bar for a staple strip,a 4staple driver mounted for movement across the end of the bar to drivea staple, means for feeding the staples along the bar to drivingposition, a spring engaging the driver for operating it, yan operatinglever, a pawl engaging a shoulder on the driver to retract the driverand tension the spring by operation oi' thai-ever, said pavvl beingprovided with an elongated slot, spaced pins' in the lever passingthrough the 'slot' to mount the pawl for sliding movement toward andfrom theshoulder, a spring tending to shift the pawl to engage saidshoulder', a can; surface on Ythe pavvl, anda stationary memberpositioned to'engagesaid cam surfaceV to shift the'pawl `to release rthedriver as it approaches its retractedposition.-

' 11. A- staple V:driving machine comprising a guide bar for a-Vstaple-strip, a staple-driver mounted for movement across the end of thebar to drive a staple, means ior feeding the staples along the bar; todriving position, a Yspring engaging the driver for operating it,an-operating lever including a pair VofY laterally;V spaced arms, a pawlmounted between said armsand engag- Yinsa ShQulder en, the .driver i0'retract the driver ROY E. PETERSON.

REFERENCES CITED The following references are of record in the le oftlhis patent:

Number UNITED STATES PATENTS Name Date Posnack Jan. 30, 1934 Case Apr.2, 1935 Hansen Sept. 22, 1936 Krantz Feb. 9, 1943 Polzer Mar. 23, 1943Heller June 13, 1944 Lang Oct. 31, 1944

